Acrylic rubber (ACM) has been used in conventional drivetrain oil seals in view of suitability for ambient temperatures at which they are used (−35° C. to 150° C.).
However, in an environment such as Latin America where it is often necessary to drive on a water-covered road, intrusion of muddy water may cause foreign matters to get stuck in a sliding portion of a sealing, leading to oil leakage due to wear of the sealing.
It has been proposed to use hydrogenated nitrile rubber (HNBR) for sealing technology. Patent Document 1 describes a composition containing a combination of HNBR and NBR and its use as a base material of a gasket. Patent Document 2 describes a composition comprising a silicone oil and a fluorinated polymer together with a rubber such as HNBR and its use for a ball bearing.